Outline

Background: Puberty is a so-called critical period for overweight and characterized by physiological insulin resistance during mid-puberty. This study addressed the hypothesis that habitual consumption of a diet inducing higher levels of postprandial glycemia or insulinemia during puberty may have an unfavorable effect on body composition in young adulthood.

Materials and Methods: Multivariate regression analysis were performed on 263 DONALD participants with at least two 3-day weighed dietary records during puberty (girls 9-14years; boys 10-15years) and anthropometric measurements in young adulthood (18-25years). A published dietary glycemic index (GI) was assigned to each carbohydrate containing food. Similarly, each food was assigned a food insulin index (insulinemic response to a 1MJ portion of food relative to 1MJ of white bread) using 121 values measured at Sydney University.

Results: Dietary GI or GL during puberty were not related to body composition in young adulthood. The dietary insulin index (II) during puberty was associated with higher levels of percentage of body fat (%BF) in young adulthood, even after adjustment for early life, socioeconomic and nutritional factors; %BF in energy-adjusted tertiles of dietary II were 23.1 (95%CI: 21.9, 24.4), 24.4 (23.2, 25.7), 24.8 (23.6, 26.0) (p for trend=0.02). Adjustment for baseline %BF attenuated this relationship (p for trend=0.1). Dietary II was not related to BMI.

Conclusion: This study suggests a prospective adverse influence of dietary II during puberty on body fat in young adulthood. Postprandial increases in insulinemia rather than increases in glycemia appear to be implicated in an unfavorable development of body composition.